Motor controller



Dem-"3, 1929. E. w. SEEGER 1, 8,

MOTOR conmomm Filed Sept. 1'7, 1928 11v VENTOR B Y w. Mm I e f I A TTORNE Y Patented Dec. 3, 1929 UNITED STATES PATENT OFFICE EDWIN W. SEEGER, OF WAUWATOSA, WISCONSIN, ASSIGNOR, BY MESNE. ASSIGNMENTS,

T CUTLER'HAMMERING, OF MILXVAUKEE, WISCONSIN, A CORPORATION OF DELA- WARE MOTOR CONTROLLER Application filed September 17, 1928. Serial No. 306,373. 1

This invention relates to motor controllers, and is particularly applicable to present speed controllers for motor driven machines, such as printing presses.

Controllers formotor driven machines of the aforesaid character are usually provided with a single speed regulating rheostat, and it is the usual practice to include for starting that portion of the resistance of the rheostat which is best suited to produce the proper torque and acceleration of the motor and to include for running that portion of the resistance of the rheostat which provides the selected running speed. However, as heretofore designed such controllers havenot been entirely satisfactory, owing to the fact that no provisionwas made for Varying the starting period in accordance with the selected running speed. Thus the starting connections were sometimes maintained until the motor accelerated to aspeed which was 1 higher than the selected running speed- The present invention has among its objects to provide an improved controller which will overcome the aforesaid objection.

. Another object is to provide a present speed controller for machines of the aforesaid character including a simple timing mechanism which provides for variation of the starting period in accordance with the setting of the speed regulating rheostat.

Various otherobjects and advantages of the invention will hereinafter appear.

The accompanying drawing illustrates an a three phase slip ring induction motor'M. having a speed regulating rheostat R associated therewith. Rheostat R is provided with the usual resistancesr r and r each to of which is connected n, one phase of the embodiment of the invention which will now secondary circuit of the motor, and the same 3 for excluding part of-the resistance of. rheostat R for starting and a three pole electromagnetic switch 4 for including for running that part of the resistance of rheostat It determined by the setting of the contact element 1. The main switch 2 is controlled through themedium of a normally closed stop push button 5 a nd a normally open starting push button 6, and as hereinafter set forth said main switch in responding maintains itself in closed position through the medium of normally open auxiliary contact t'l Also, as hereinafter set forth the main itch auxiliary contacts 2 provide for energization of the starting switch 2 through the medium of normally closed auxiliary contacts 4: associated with the running switch 4 and for establishment of the energizing circuit of runningswitch 3 through the medium'of a timing switch 8. V

Timing switch 8 includes a pair of cooperbeing associated with main switch 2 and the latter with the control element 1 of rheostat R. Contact .9 is connected to a projecting arm 11 on main switch 2 through the medium of a spring 12, and upon closure of said main switch said arm moves upwardly under the'action of said spring against the action of a dashpot13. Contact 10 is fixed to one arm of a bell crank 14 and the other arm of i said bell crank is connected by a link 15 to the control element 1 of rheostat R.- It is thus apparent that the angular position of the bell crank 14: is dependent upon the setting of the control element 1 of rheostat R,

and as is apparent variation of the angular position of the bell crank 14 varies the time required for movement ofcontact 9 from the position shown in Fig. 1. into engagement with contact 10 upon closure of main switch 2.

The operation and circuit connections of the controller will now be more fully described, reference being made to Fig. 2 in connection with the description of the control circuits. As is apparent from Fig. 2 depression of push button 6 connects the operating winding 2 of main switch 2 across lines L *L through the medium of the stop push button 5 and upon closure of said main switch the auxiliary contacts 2 thereof shunt the push button 6 to maintain said main switch energized upon release of push button 6. Also as is apparent from Fig. 2 immediately upon closure of main switch 2 the auxiliary contacts 2? thereof connect the operating winding 3 of starting switch 3 across lines L L through the medium of the stop push button 5 and the auxiliary contacts 4* associated with running switch Starting switch 3- is connected to the resistances of rheostat B so that upon closure thereof a part of the rheostat resistance is excluded from the secondary circuit of the motor to produce the desired torque and acceleration of the motor.

Immediately upon closure of main switch 2, spring 12 is placed under tension to effect upward movement of contact 9 against the action of dash pot 13. Upon movement of contact 9 into engagement with contact 10 the operating winding of running switch t is connected across lines L L through the medium of the stop push button 5 and the auxiliary contacts '2 associated with main switch 2 and immediately upon response of said running switch the auxiliary contacts l thereof interrupt the aforedescribed energizing circuit for starting switch 2. Closure of running switch t connects the three contact arms of the rheostat R together to thereby include in the secondary circuit of motor M a selected part of the resistance of the rheostat determined by the setting of the contact element 1.

Movement of the contact element 1 in a clockwise direction increases the running resistance in the secondary circuit of the motor and effects downward movement of contact 10, while movement of said contact element in an opposite direction decreases the running resistance in such circuit and eflfects upward movement of contact 10. The time required to effect movement of contact 9 into engagement with contact 10 upon closure of main switch 2 thus varies in accordance with the running speed selected by rheostat R. The dash pot 13 is calibrated so thatthe same provides for upward movement of contact 9 at a rate which provides for interruption of starting connections and establishment of running connections when the motor accelerates to a speed which is substantially the same as the running speed selected by rheostat R.

In connection with the foregoing it should be noted that the controller is not limited to use in connection with motors of the type illustrated in the drawing, and if desired tim ing devices of other types can be employed.

'What I claim as new and desire to secure by Letters Patent is:

1. In a motor controller, the combination with switches for selectively establishing starting and running connections for the m0- tor, of an associated resistance device adjustable to effect selection of the running speed of the motor, and control means for said switches including timing means associated with said device to delay establishment of running connections for an interval which is a function of the speed selected by said device.

2. In a motor controller, the combination with a resistance to be connected in the motor circuit, of a switch for utilizing a portion of said resistance for starting, a second switch for utilizing another portion of said resistance for running, a device for varying the value of said last mentioned resistance portion for selection of the running speed 01 the motor, and control means for said switches including means associated with said device for delaying interruption of starting connections and establishment of running connections by said switches for a period which is a function of the running speed of the motor selected by said device.

3. In a controller for slip ring induction motors, in combination, a resistance connected to the slip rings of the motor, switches for utilizing a portion of saidresistance for starting and another portion thereof for running, a device for varying the value of said last mentioned resistance portion for selection of the running speed of the motor and control means for said switches including a device associated with said resistance varying means for timing the operation of said switches.

4. A controller for electric motors comprising an electromagnetically operated starting switch and means for energizing the same, an electromagnetically operated running switch, means for effecting selection of the speed of said motor upon closure of said running switch and means set in operation upon closure of said starting switch to effect closure of said running switch after an interval which is a function of the motor speed selected by said former means.

5. A controller for electric motors comprising two electromagnetically operated switches, one for establishing starting connections and the other for establishin running connections, means associated wit 1 said latter switch for effecting selection of the running speed of the motor, a timing device adapted to act upon establishment of starting connections for the motor to efleet closure of said running switch after an interval which is a function of the speed of'the motor selected by said device, and means acting upon closure of said running switch to effect deenergization of said starting switch.

6. A controller for electric motors comprising two electromagnetically operated switches, one for establishing starting connections for the motor and the other for establishing running connections therefor, a resistance device connected in the motor circuit and including an adjustable part for effecting selection of the running speed of the motor upon closure of saidrunning switch and means including a spring actuateddevice for controlling said switches to elfect interruption of starting connections and establishrnent of running connections, said de vice being associated with said resistance varying part to provide for maintenance of the starting connections-for a period which is a function of the motor speed selected by said device.

In witness whereof, I have hereunto subscribed my name.

EDWIN W. SEEGrER.

CERTIFICATE OF CORRECTION.

Patent No. 1,738,155. Granted December 3, 1929, to

EDWIN W. SEEGER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, lines 2 and 26, for the word "present" read "preset"; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 4th day of March, A. D. 1930.

M. J. Moore, (Seal) Acting Commissioner of Patents,

CERTIFICATE OF CORRECTION.

Patent No. 1,738,155. Granted December 3, 1929, to

EDWIN W. SEEGER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, lines 2 and 26, for the word "present" read "preset"; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 4th day of March, A. D. 1930.

M. J. Moore, (Seal) Acting Commissioner of Patents, 

